/*
 * Integrated Rule Inference System (IRIS):
 * An extensible rule inference system for datalog with extensions.
 * 
 * Copyright (C) 2008 Semantic Technology Institute (STI) Innsbruck, 
 * University of Innsbruck, Technikerstrasse 21a, 6020 Innsbruck, Austria.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, 
 * MA  02110-1301, USA.
 */
package org.deri.iris.storage.simple;

import java.util.List;

import org.deri.iris.api.basics.ITuple;
import org.deri.iris.storage.IRelation;
import org.deri.iris.utils.UniqueList;

/**
 * A simple, in-memory, array-based relation.
 */
public class SimpleRelation implements IRelation
{
	/**
	 * Constructor.
	 * For performance reasons where the user of the class can enforce uniqueness
	 * (or does not require it), uniqueness enforcement can be turned off.
	 * @param forceUniqueness true, if this object should enforce uniqueness.
	 */
	SimpleRelation()
	{
		mTuples = new UniqueList<ITuple>();
	}

	public boolean add( ITuple tuple )
	{
		assert mTuples.isEmpty() || ( mTuples.get( 0 ).size() == tuple.size() );
		
		return mTuples.add( tuple );
	}

	public boolean addAll( IRelation relation )
	{
		boolean added = false;
		
		for( int i = 0; i < relation.size(); ++i )
			if( add( relation.get( i ) ) )
				added = true;
		
		return added;
	}

	public ITuple get( int index )
	{
		return mTuples.get( index );
	}

	public int size()
	{
		return mTuples.size();
	}
	
	public boolean contains( ITuple tuple )
	{
		return mTuples.contains( tuple );
	}

	@Override
    public String toString()
    {
		return mTuples.toString();
    }

	/** The array list (or unique list) of tuples. */
	private final List<ITuple> mTuples;
}
